Case IH 3658 – Engine Control Module (ECM): ECU Power stages : SPI/COM-Errors of the power failure detection of CY320

An internal hardware/communication error within the engine computer triggered when the ECU detects a Serial Peripheral Interface (SPI) or communication failure between the internal power stage chips and the CY320 voltage supplier chip.

• Maxxum
• Puma
• Farmall
• Steiger
• Axial-Flow

1. 1

   Check battery voltage to ensure the charging system and batteries are delivering a stable 12V-14V (or 24V). High or low voltage can disable power stage diagnosis and trigger related codes.

2. 2

   Inspect the wiring harness supplying power and ground to the ECM. Verify connections are clean, tight, and free of corrosion or short circuits to prevent voltage drops.

3. 3

   Check for available software updates for the ECM using the CNH Electronic Service Tool (EST).

1. 1

   Reflash the ECM

   Connect the CNH EST diagnostic tool and attempt to flash the ECM correctly with a proper, updated dataset.

2. 2

   Cycle Power

   After the flash is complete, clear the inactive fault codes and cycle the ignition key.

3. 3

   Replace the ECM

   If the 3658 fault code persists or immediately returns after reprogramming, the internal CY320 chip or its communication bus is permanently damaged and you must replace the entire Engine Control Module.